Electronystagmography (ENG) is commonly prescribed for the evaluation of patients with vestibular or neurological dizziness, vertigo, and/or disequilibrium. Although the ENG exam is routinely performed in a clinical setting, the majority of a patient's vertiginous episodes occur outside of the physician's office. The ability to observe and document these 'naturally occurring' eye movements would seem important for a thorough ENG evaluation. The InfraRed/Video ENG System is an established method for the recording of eye movements using video cameras, invisible infrared illumination and associated computer technology. This method of recording documents bilateral, monocular eye movements (horizontal, vertical and rotary components). The Phase I work effort will configure the current IR/Video ENG System into a portable model to be used by a pilot group of House Ear Clinic patients during their 'naturally occurring' vertiginous episodes (at home, in the workplace, during travel, etc.). These videotaped responses will then be clinically reviewed and analyzed with the current InfraRed/Video ENG System. The results will be correlated to the patient's normal clinical workup findings to assess the advantages of this additional IR/Video ENG capability.